The correct option is A his/he/hers/her
The first blank indicates possession by third person singular masculine pronoun in the subjective sense(his), the second blank indicates the pronoun as the subject of the verb "accepted" (he), the third blank indicates possession by third person singular feminine pronoun in the objective sense(hers) and the last blank indicates the pronoun as the object of the verb "thanked"(her). Hence, Option A is correct. The rest of the options do not adhere to this rule, hence incorrect.